Kansas City's No. 2 prospect as ranked by MLB.com struck out a career-high 13 on Tuesday, allowing just one run on four hits over six innings of work in Class A Advanced Wilmington's 8-1 win over Frederick.

"Everything felt pretty good. All four of my pitches, I was able to throw for strikes," Zimmer told MiLB.com. "My fastball command felt really good. I got ahead of their hitters and finished them off pretty well when I got to two strikes. I was just getting ahead, being aggressive in the zone. I felt like I was able to move the fastball back and forth across the plate and throw my curveball for strikes -- elevate the fastball to get some swing-throughs and had the curve sharp in the zone."

With little pitching experience under his belt, Zimmer is still learning every day. But he has a plus-fastball and an incredible strikeout rate that looks promising for the Royals' future.

The fifth overall pick in the 2012 Draft, Zimmer struggled this season, his first in high-A ball. After 13 starts he had a 5.98 ERA. Since then he's posted a 2.77 ERA and fanned 32 in 26 innings.

"I feel like my mechanics are starting to come together. I'm staying on line pretty well, throwing all my pitches in the zone and being able to pitch guys backwards," he told MiLB.com. "I can manipulate my fastball, just been working on attacking the zone more consistently. Working on my mechanics, staying on line with my front side. There were a couple starts where there was just one big inning hurting me, so I've been able to avoid those innings lately."

This story was not subject to the approval of Major League Baseball or its clubs.